Hi All I completely agree with Mike about the importance of a good low Z ground. I have my own version of a Poly-Phaser entry panel connected via a 6" wide copper strap to a multiple ground rod system with 12 Ga. radials, and the whole shack is bonded to that through a 2" wide ground buss with 1" wide braid jumpers to each piece of equipment. But........ I recently had an amusing (in the final outcome) Lightning experience. I just bought a super duper UPS with surge protection and auto shut down via USB and all that. We had a thunder storm come through the other day, and all seemed well until I was in the next room getting ready for bed about 1:00 A.M. I heard a pop from my computer / radio area, went in there, but couldn't find anything. But I did not try turning on anything. The next morning when I did try to turn on the computer, no luck. I was pretty sure that despite the grounding system and my new UPS I had taken a lightning hit. Which annoyed me greatly. I replaced the power supply in the computer, it came up just fine and all was well. Being curious, after a day or so, I opened the old power supply which by now had a curious smell. I found a chip with the top blown off, and a dead gecko. Apparently it had gotten in (those little bastards can get in anywhere) and had gotten across some part in the power supply that is active at all times causing the chip to blow by shorting something down stream, and in the process went to meet it's maker. Taking my power supply with it. Bill AD5OL
----- Original Message ---- From: Mike Naruta <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Cc: [email protected] Sent: Wednesday, July 19, 2006 9:33:24 AM Subject: Re: [Flexradio] SDR1000 Damaged. Make sure you turn it OFF when you walk away. Update My philosophy on AC power and lightning: A LOW-impedance ground system. Lots of copper in the Earth is money well spent. Choose one location to bond everything together in the house and bring the connections to the outside world through at that point. Telephone, cable, antennae, water, and power, if possible. At that common point, use protectors to encourage the current to flow to the Earth rather then through your equipment. Check out my bonding plate at hamsdr.com I throw some Ferrite on the shack-side of the common point. This helps with RF, but the Ferrite would probably saturate on a strike. Industrial-strength MOVs at the power panel, and more MOVs/protectors at critical items. BTW, this has an interesting effect when you are running on the generator. It teaches you to watch your RPM. Brute-force C-L-C line filters on the shack branch circuit. We have a couple of UPS on our PCs. PCs just don't tolerate any power interruption. I miss the HP-3000. If you could keep the remote users from resetting their terminals, it would recover to their last screen transaction. Your wildest voltage excursions are likely to be just before and just after a power outage. I like the idea of a holding relay. It gives you a chance to wait until the power stabilizes before turning your gear back on. I may put a contactor in the shack branch circuit. You could also rig up over-voltage and under-voltage protection. Mike - AA8K [EMAIL PROTECTED] wrote: > Just a bit on my philosophy about turning things off and on. > > Ages ago I worked for a company that made computer peripherals. An > account I was dealing with had hundreds of Smart CRT terminals. > Any time a storm was in the area we would cringe because we knew if > the power went out some(a lot) of those terminals wouldn't come > back on line. We might have to zig zag across the state to repair > them. The failures were always attributed lightning or surges on > the power or data lines. > > > My philosophy about lightening protection: Yous pays yous money and > yous take yous chances. > > On the air since 1971 this is my first damage from lightening. > $1.50 for the part from Digikey. If it happens again I reserve the > right to change my philosophy. :) > > Mileage Does Vary, > k2ox > _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/flexradio_flex-radio.biz/attachments/20060719/b855703a/attachment.html _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
